The invention relates generally to navigation and communications and, in particular, to a combination network interface card and Global Positioning System receiver.
Computers have become an invaluable, if not indispensable, tool for a broad array of business and industrial applications, as well as for personal use. For many applications, it is desirablexe2x80x94and, in some instances, necessaryxe2x80x94to have access to a computer network, such as a Local Area Network (LAN), Wide Area Network (WAN), or the Internet. A computer typically obtains access to a computer network using a network interface card, or NIC. A NIC is an expansion board or peripheral card installed in, or coupled with, a computer that provides a connection to a computer network. The connection may comprise a physical connection (e.g., cable or fiber optic) or a wireless connection. A device driver resident on the host computer controlsxe2x80x94in conjunction with an operating system resident on the hostxe2x80x94the physical functions of the NIC and coordinates data transfers between the NIC and host computer. Conventional NICs, which are also commonly referred to as network adapters or network interface controllers, typically perform only those functions associated with maintaining the connection between the host computer and the computer network.
Many computer users utilize their computer as a navigational aide to obtain precise geographical or navigational information (e.g., latitude, longitude, elevation) or to run applications requiring such precise navigational data. This navigational data can be obtained using the Global Positioning System (GPS). GPS is a collection of satellites orbiting above the Earth which transmit signals that can be detected using an appropriately configured receiver (i.e., a xe2x80x9cGPS receiverxe2x80x9d). If the signals from an adequate number of satellites are detected, these GPS signals can be used to determine the location of the GPS receiver. A general purpose computer can be adapted to obtain GPS signals by outfitting the computer with a GPS receiver provided on an expansion board or peripheral card, such GPS expansion boards and peripheral cards being well known in the art.
A computer having a network connection as well as the ability to receive and process GPS signals may be useful in a variety of applications, including surveying, fleet management, tracking and scheduling of commercial vehicles, rail car tracking, hazardous materials tracking, collision avoidance, vehicle-to-roadside services, automobile navigation, as well as marine, aviation, and space navigation. In addition, GPS signals are a source of accurate time data, providing a global-wide, consistent time reference. Also of interest is the ability to receive Differential GPS (DGPS) corrections in real time via a network connection. DGPS systems, such as the Wide Area Augmentation System (WAAS) and the Local Area Augmentation System (LASS), provide error compensation and improve GPS position determinations using one or more GPS receivers fixed at known locations.
Presently, constructing a computer that is both network ready and GPS enabled requires the installation of both a NIC and a GPS receiver. A variety of network interface cards are commercially available, as are expansion boards or peripheral cards providing a GPS receiver and associated processing. However, the introduction of both a NIC and a GPS receiver into a computer chassis consumes scarce volume and slot or card space. The addition of a NIC and a separate GPS receiver can be especially problematic for smaller computersxe2x80x94such as laptop computers, notebook computers, and hand-held computersxe2x80x94and it is these smaller computers that are most desirable for mobile applications requiring navigational data and processing. Further, although a GPS receiver is capable of providing an accurate time source (for use in, e.g., monitoring network traffic), the time information may not be directly available to the NIC, which is a separate component.